var obj = {
    '哈哈': 3,
    value: 1
};
function foo(o) {
    o = 2;//虽然传递的是对象 但o是value值
    console.log(o); //2
}
foo(obj);
console.log(obj.value) // 1

console.log('-----');
const arguments = {
    0: foo,
    1: 'kevin',
    2: 18,
    length: 3
}
// 因为arguments是类数组对象，所以可以用for循环
var args = [];
for (var i = 0, len = arguments.length; i < len; i++) {
    args.push(arguments[i]);
}
console.log(args, '---1');
console.log(Array.from(arguments));

function test() {
    console.log([...arguments]);

}

test(1, 2, 3, 4)
